Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for North America Nebula: 04-06 (57), 04-05 (51), 04-04 (44), 03-19 (43), 03-21 (43) — by astronomy; check the weather when the night is within four days.

2040-03-08astronomy score per night — click a bar for that night2040-04-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-03-08 Thu	32	—	unknown	03:55–05:10 (good, 1.25 h)	87.2° 10:10	9.29	22%	71.3°
2040-03-09 Fri	34	—	unknown	03:50–05:10 (good, 1.33 h)	87.2° 10:05	9.24	13%	66.8°
2040-03-10 Sat	35	—	unknown	03:50–05:10 (good, 1.33 h)	87.2° 10:05	9.19	6%	63.8°
2040-03-11 Sun	35	—	unknown	03:45–05:05 (good, 1.33 h)	87.2° 10:00	9.15	2%	62.5°
2040-03-12 Mon	37	—	unknown	03:40–05:05 (good, 1.42 h)	87.2° 09:55	9.1	0%	63.1°
2040-03-13 Tue	38	—	unknown	03:35–05:05 (good, 1.5 h)	87.2° 09:50	9.05	1%	65.3°
2040-03-14 Wed	38	—	unknown	03:30–05:00 (good, 1.5 h)	87.2° 09:45	9.0	4%	68.8°
2040-03-15 Thu	39	—	unknown	03:30–05:00 (good, 1.5 h)	87.2° 09:45	8.95	10%	73.4°
2040-03-16 Fri	40	—	unknown	03:25–05:00 (good, 1.58 h)	87.2° 09:40	8.9	16%	78.5°
2040-03-17 Sat	40	—	unknown	03:20–04:55 (good, 1.58 h)	87.2° 09:35	8.84	24%	84.0°
2040-03-18 Sun	42	—	unknown	03:15–04:55 (good, 1.67 h)	87.2° 09:30	8.79	33%	89.6°
2040-03-19 Mon	43	—	unknown	03:10–04:55 (good, 1.75 h)	87.2° 09:25	8.74	42%	95.1°
2040-03-20 Tue	42	—	unknown	03:10–04:50 (good, 1.67 h)	87.2° 09:25	8.69	52%	100.4°
2040-03-21 Wed	43	—	unknown	03:10–04:50 (good, 1.67 h)	87.2° 09:20	8.64	61%	105.3°
2040-03-22 Thu	42	—	unknown	03:10–04:45 (good, 1.58 h)	87.2° 09:15	8.59	70%	109.6°
2040-03-23 Fri	42	—	unknown	03:10–04:45 (good, 1.58 h)	87.2° 09:10	8.53	78%	113.2°
2040-03-24 Sat	38	—	unknown	04:05–05:45 (good, 1.67 h)	87.2° 10:10	8.48	86%	115.8°
2040-03-25 Sun	38	—	unknown	04:00–05:40 (good, 1.67 h)	87.2° 10:05	8.43	92%	117.3°
2040-03-26 Mon	38	—	unknown	04:00–05:40 (good, 1.67 h)	87.2° 10:00	8.37	97%	117.3°
2040-03-27 Tue	37	—	unknown	04:00–05:40 (good, 1.67 h)	87.2° 09:55	8.32	99%	115.8°
2040-03-28 Wed	36	—	unknown	03:55–05:35 (good, 1.67 h)	87.2° 09:50	8.27	100%	112.9°
2040-03-29 Thu	34	—	unknown	03:55–05:35 (good, 1.67 h)	87.2° 09:50	8.21	98%	108.7°
2040-03-30 Fri	33	—	unknown	03:55–05:30 (good, 1.58 h)	87.2° 09:45	8.16	94%	103.4°
2040-03-31 Sat	33	—	unknown	03:50–05:30 (good, 1.67 h)	87.2° 09:40	8.1	87%	97.4°
2040-04-01 Sun	34	—	unknown	03:45–05:30 (good, 1.75 h)	87.2° 09:35	8.05	79%	91.0°
2040-04-02 Mon	35	—	unknown	03:40–05:25 (good, 1.75 h)	87.2° 09:30	7.99	68%	84.6°
2040-04-03 Tue	38	—	unknown	03:30–05:25 (good, 1.92 h)	87.2° 09:30	7.94	57%	78.4°
2040-04-04 Wed	44	—	unknown	03:10–05:20 (good, 2.17 h)	87.2° 09:25	7.88	46%	72.7°
2040-04-05 Thu	51	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:20	7.83	35%	68.1°
2040-04-06 Fri	57	—	unknown	03:00–05:20 (good, 2.33 h)	87.2° 09:15	7.77	24%	64.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-03-08&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.